The present invention is directed to a dental handpiece arrangement having a drive motor with a drive shaft and a grip piece containing a grip sleeve with a head housing having a chuck arrangement to hold a tool which is rotated by a drive train that is connected to the drive shaft of the drive motor.
It has been known for a long time in dental technology to mount with a removable connection a handpiece part essentially containing a head housing with a gripping sleeve connected thereto which is referred to in the technical field as a "hand and angle piece" on a drive part containing a drive motor. The connection is thereby designed such that in its emplaced condition, the hand and angle piece can be rotated relative to the drive part while retaining the drive shaft connection. The coupling and uncoupling occurs by means of a rapid coupling via a guide pin which surrounds the drive shaft of the drive part as disclosed in U.S. Pat. No. 3,604,960.
The construction of such a handpiece arrangement has been retained even with the introduction of what is referred to as an incorporated spray arrangement, i.e., the guidance of a cooling agent such as air and water within the drive parts and within the hand and angle piece. The guidance of the agent within the drive part is between the stator and motor housing and the agent is delivered at the guide pin for transfer to the grip piece through a fluid coupling arrangement which includes radially extending ports in one of the guide pins or socket of the grip piece and the other of the guide pins and socket having annular channels with O-ring seals for receiving the discharge from the ports. Such an arrangement is disclosed in U.S. Pat. No. 4,007,529.
In addition to these conventional handpiece arrangements, a handpiece arrangement wherein the gripping sleeve normally remains on the drive part and only relative short treatment heads containing the head housing are coupled to the drive part in an easily releasable fashion have also become common in recent years. The gripping sleeve will have a sleeve extending over the drive part which contains the agent guidance, and the gripping sleeve itself is only removed from the drive part for sterilization purposes. The gripping sleeve and the treatment head are freely rotatable relative to the drive part but the sleeve extending over the motor is not and it is capable of being withdrawn from the drive part together with the gripping sleeve as disclosed in U.S. Pat. No. 4,251,212.
In this handpiece system, the agent guidance occurs within the drive part and the agent delivery occurs via correspondingly fashioned fluid couplings between the guide pin and a socket in the handpiece.
Recently, it has become desirable to offer a motor-driven handpiece arrangement with an incorporated light guidance and this would initially mean providing additional variations of the handpieces with light guidance which handpieces would no longer be compatible with the handpiece arrangements heretofore commercially available. This would particularly affect the motor side where drives with and without light would have to be offered for coupling the one or the other handpiece systems explained above.